Your point is valid. however a society with a certain amount of angst and suffering and struggles is a society that prospers and advances at a slightly faster pace. There is a fine line though...between the enhanced prosperity and utter collapse/destruction. Too much chaos and it all falls apart.
I agree. The phenomenon you describe applies to people, corporations and societies. Some sociologists call it "creative tension."
Your point is that too much homogeneity does not foster enough creative tension to move it forward quickly.